Hi, my name is

Software Engineer

I’m a frontend software engineer with 2+ years of experience in performance-critical web development, specializing in React/Next.js and server-side rendering. I work mainly in fintech and payments — shipping fraud-prevention, compliance, and performance-optimization features for high-traffic products.

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Portrait of Qalbun Salim

Professional Experiences

Traveloka

Software Engineer - Paylater

Jan 2025 - Present

  • Cut repayment page LCP by ~60% (5.2s → 2.1s) and CLS by ~77% (0.2541 → 0.0578) via server-side rendering.
  • Led partial repayment frontend, validated by A/B test (2.79% → 3.22%) for a 15.45% relative uplift in repayment rate.
  • Built an authentication challenge module embedding dynamic PIN, OTP & NIK checks in a webview to deter fraud across Paylater flows.
  • Built a subledger transaction visualization tool, cutting check time by 90%.
  • Implemented Android digital signature for offline payments to meet OJK compliance.
  • Built AI-driven live browser testing with Claude subagents to verify code changes.

Software Engineer Intern - Corporate Travel

Feb 2024 - Dec 2024

  • Revamped the B2B Corporate Travel landing page with a dynamic marquee showcasing 2,000+ partner companies.
  • Redesigned admin company-management UI, unifying Travel Policy, Employee List, and Approval System into one streamlined workflow.

Universitas Indonesia

Automata Theory Teaching Assistant

Aug 2022 - Jan 2023

  • Graded homework for 23 students across finite state machines to Turing machines.
  • Mentored 5 students with weekly lessons and exam prep on automata theory.

Toolbox

What I work with

The tools I actually use to build and ship things, grouped by how often they land in my work day.

Core · daily drivers

Comfortable · steady

Learning · sharpening

Featured Projects

Things I’ve built and continue to explore

CopyFlow

2025

CopyFlow

Automated copywriting workflow in Lark — from first draft to launch.

Team entry to Traveloka's 2025 Lark Efficiency Pioneer Competition. CopyFlow replaces manual copywriting handovers with a single automated Lark workflow: a Figma link populates a Lark Base as the source of truth, an LLM co-pilot keeps every draft on-brand, and approval-triggered automation delivers translated, locale-ready copy to POEditor and in-house content tools.

  • Figma link populates a Lark Base as the single source of truth
  • LLM co-pilot keeps every draft consistent with company tone standards
  • Approval-triggered handoffs with AI translation across all locales
Lark
Automation
LLM
Amazon Bedrock
Chess PTP

2025

Chess PTP

Peer-to-peer chess over WebRTC, no game server.

Chess online or locally, moves peer-to-peer over WebRTC.

Vue
Vite
TypeScript
chess.js
WebRTC
Firebase

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